Keeping clean coal on course

In Indiana, USA, the River View mine is producing more than a million tons of clean coal a month. So much in fact, that an 8,000-foot long dam has had to be built to contain the mine’s slurry lake.

Alliance Resource Partners’ River View mine, located along the Ohio River near Evansville, Indiana, is known as having the most productive continuous mining operations in the Illinois Basin. In just its first year of operation, in 2010, the underground mine produced more than 5.8 million tons of clean coal. Since then, Alliance Resource Partners has ramped up production to more than a million tons of coal a month.

“Market conditions are great for us at the moment,” says Mark Henshaw, project engineer at Alliance Resource Partners, “but at this rate of production, keeping track of our refuse is a daily challenge.”

Raw coal mined from the site is conveyed to a preparation plant where it is sorted into clean coal and coarse refuse, consisting of fine clays, shale or slurry. The clean coal is stockpiled and later loaded on to barges for transportation across the Ohio River – but the refuse and slurry, which make up 35% of the raw material feed, needs to be disposed of. “We need to get the waste material away from the preparation plant quickly. If we don’t, the whole operation shuts down,” says Henshaw.
A constant streamThe waste slurry is pumped into a 55-acre impoundment lake while the coarse refuse – produced at a rate of 285,000 tons a month (570 tons an hour) – is conveyed to a refuse bin nearby. The refuse bin only holds 300 tons, so production relies entirely on hauling refuse away from the bin.

“If the haulers can’t run, we’re in trouble.” says Henshaw. “That’s why we chose Volvo. Volvo Construction Equipment has an excellent reputation for quality and reliability – and they haven’t let us down.”

Alliance Resource Partners maintains a fleet of four Volvo A40E FS articulated haulers, which are sold and serviced by Rudd Equipment, the Volvo Construction Equipment (Volvo CE) dealer based in Evansville. The company has owned three Volvo articulated haulers since the mine first opened. The machines run around the clock, five days a week, and cover more than 135 miles (217 km) a day. “We don’t calculate their availability, but we know it’s very good,” says Henshaw. At a rate of 145 tons an hour, the A40E FS haulers transport waste from the refuse bin to the edge of the slurry lake, where it is used to build an 8,000-foot (2,438-meter) long impoundment dam.

The Volvo haulers typically dump their loads in one place and dozers spread it out in one-foot (30-cm) lifts away from the slurry lake. At the top of the dam, the haulers work their way up and over to the lake. As soon as the dam reaches 30 feet (9.1 m) wide, the coarse material is pushed out into the slurry pond. In some parts the dam is as wide as 80 feet (24.3m).

Six wheels are better than fourRegulations demand that the slurry material meet a certain compaction regulation. The Volvos’ six-wheel drive means that Alliance Resource Partners’ operators can drive over virgin fill, where other machines would fear to tread. This packs down the surface, eliminating the need for an additional compaction machine.

Lloyd Patton, who operates one of the A40E FS haulers, says: “We lock into the six-wheel drive on just about every load. Without it we would just sink. The area receives 42 to 48 inches (1,067 to 1,219 mm) of rainfall every year – most of it during November and March. It gets pretty slippery when it’s wet, and if we had to use a rigid-frame truck, it would be like putting a bull on ice.”

A fleet of rigid-frame trucks would also require two extra operators, adding extra costs to maintain the haul roads and fill area. “Our Volvo machines allow us to keep running a steady rate of production throughout the year, keeping operational costs to a minimum,” Henshaw adds.
A smooth rideThe Volvo A40E FS articulated haulers also feature full suspension, a feature greatly appreciated by River View managers and operators alike.

“The trucks ride very smoothly,” says Henshaw. “Full suspension doesn’t necessarily aid fuel economy, but with this feature an operator is going to move more material per gallon of fuel. Full suspension increases production by about 10 to 15 percent compared to non-FS equipped haulers Volvo CE articulated haulers really are the best in the business.”

June 2013

Picture 1: The A40E FS haulers transport waste from the refuse bin to the edge of the slurry lake.